Studies in progress and projected for the near future include an examination of the anomeric identity of F-1, 6-diP that activates yeast pyruvate kinase. Having established that phosphofructokinase is beta- specific, we will employ the enzyme to rapidly synthesize a pulse of beta-f-1, 6-diP and observe the effect of this anomer relative to equilibrated F-1, 6-diP on the activation of the kinase. Additional "coupled experiments" with phosphofructokinase and fructose- bisphosphatase will be carried out in order to test whether the immediate product of the phosphatase reaction cannot be directly utilized by the kinase, i.e. with increased amounts of phosphofructokinase, the concentration of F-6-P will reach a limiting steady-state value.